Zirconia sintered body having high linear light transmittance

Abstract

A zirconia sintered body may excel in translucency, strength, and linear light transmittance with no use of an HIP device, and a zirconia molded body and a zirconia pre-sintered body from which such a zirconia sintered body can be obtained. A zirconia molded body may include zirconia particles with 2.0 to 9.0 mol % yttria, an average primary particle diameter of 60 nm or less, and 0.5 mass % or less zirconia particles having a particle diameter >100 nm, wherein the zirconia molded body has ΔL*(W−B) of 5+ through a thickness of 1.5 mm. A zirconia pre-sintered body may include 2.0 to 9.0 mol % yttria, and have a ΔL*(W−B) of 5+ through a thickness of 1.5 mm. A zirconia sintered body may include: a fluorescent agent; 2.0 to 9.0 mol % yttria, and have a linear light transmittance of 1% or more through a thickness of 1.0 mm.

The invention claimed is: 
     
       1. A zirconia molded body, comprising:
 zirconia particles comprising 2.0 to 9.0 mol % yttria, having an average primary particle diameter of 60 nm or less, and including 0.5 mass % or less zirconia particles having a particle diameter of more than 100 nm, 
 wherein the zirconia molded body has a ΔL*(W−B) of 5 or more through a thickness of 1.5 mm. 
 
     
     
       2. The zirconia molded body of  claim 1 , wherein the zirconia molded body has a three-point flexural strength of 500 MPa or more after being sintered at 900 to 1200° C. under ordinary pressure. 
     
     
       3. The zirconia molded body of  claim 1 , wherein the zirconia molded body has a transmittance of 40% or more for light of 700 nm wavelength through a thickness of 0.5 mm after being sintered at 900 to 1200° C. under ordinary pressure. 
     
     
       4. The zirconia molded body of  claim 1 , wherein the zirconia molded body comprises a monoclinic crystal system in a fraction of 5% or less with respect to a tetragonal crystal system and a cubic crystal system after being sintered at 900 to 1200° C. under ordinary pressure and then immersed in 180° C. hot water for 5 hours. 
     
     
       5. The zirconia molded body of  claim 1 , wherein the zirconia molded body has a ΔL*(W−B) of 5 or more through a thickness of 1.5 mm after being sintered at 200 to 800° C. 
     
     
       6. A zirconia pre-sintered body, comprising:
 2.0 to 9.0 mol % yttria, 
 wherein the zirconia pre-sintered body has a ΔL*(W−B) of 5 or more through a thickness of 1.5 mm. 
 
     
     
       7. The zirconia pre-sintered body of  claim 6 , wherein the zirconia pre-sintered body has a three-point flexural strength of 500 MPa or more after being sintered at 900 to 1200° C. under ordinary pressure. 
     
     
       8. The zirconia pre-sintered body of  claim 6 , wherein the zirconia pre-sintered body has a transmittance of 40% or more for light of 700 nm wavelength through a thickness of 0.5 mm after being sintered at 900 to 1200° C. under ordinary pressure. 
     
     
       9. The zirconia pre-sintered body of  claim 6 , further comprising:
 a monoclinic crystal system in a fraction of 5% or less with respect to a tetragonal crystal system and a cubic crystal system after being sintered at 900 to 1200° C. under ordinary pressure and then immersed in 180° C. hot water for 5 hours. 
 
     
     
       10. A method for producing a zirconia pre-sintered body, comprising:
 pre-sintering the zirconia molded body of  claim 1  at 200 to 800° C. 
 
     
     
       11. A zirconia sintered body comprising:
 a fluorescent agent; and 
 2.0 to 9.0 mol % yttria, 
 wherein the zirconia sintered body has a linear light transmittance of 1% or more through a thickness of 1.0 mm. 
 
     
     
       12. The zirconia sintered body of  claim 11 , wherein the zirconia sintered body has a three-point flexural strength of 500 MPa or more. 
     
     
       13. The zirconia sintered body of  claim 11 , wherein the zirconia sintered body has a transmittance of 40% or more for light of 700 nm wavelength through a thickness of 0.5 mm. 
     
     
       14. The zirconia sintered body of  claim 11 , further comprising:
 a monoclinic crystal system in a fraction of 5% or less with respect to a tetragonal crystal system and a cubic crystal system after being immersed in 180° C. hot water for 5 hours. 
 
     
     
       15. A method for producing a zirconia sintered body, comprising:
 sintering the zirconia molded body of  claim 1  at 900 to 1200° C. under ordinary pressure. 
 
     
     
       16. A method for producing a zirconia sintered body, comprising:
 sintering the zirconia pre-sintered body of  claim 6  at 900 to 1200° C. under ordinary pressure.